Shoe goop also works well (in the red tube), though the original (blue tube) is always a safe bet. That and gorilla tape will do **** near any surround repair.
As far as replacing just the foam, probably not going to happen. It's a horrible pain in the arse to scrape foam away from the cone and not much better to clean the basket down to bare metal. Also most of the companies that sell ONLY the foam are mostly foams for older home and PA speakers and will almost definitely not have anything as thick or rugged as what you want.
From there, even assuming you can get a raw surround, you'll need to pull off the dustcap and shim up the coil before glueing. You can not simply replace the cone since the cone/coil joint is typically the strongest bond of the whole thing and unless you built it yourself who knows what kind of glues were used? If you use only CA glue you can recycle the coil by soaking it in some acetone, otherwise if it's some sort of epoxy it's a done deal and you'll never get the coil free from spider and cone.